Scientists at the Broad Institute have recently reported the use of the new molecular biology tool CRISPR to aid in the detection of disease-causing agents in our system. It could soon be used as a reliable and low-cost method for diagnosing various infections such as Dengue or Zika infections in humans.

The latest sensation in molecular biology: CRISPR

Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR) are defense mechanisms used by bacteria to protect themselves against invading viruses. Viruses frequently integrate their own genome into bacterial DNA. Once integrated, the viral genome uses the bacterial system to make its own proteins.

The CRISPR system allows bacteria to excise viral gene sequences present in their genome. Over the last decade, this system has been heavily exploited by molecular biologists all over the world to excise and edit the genome of many different organisms such as plants, zebrafish, mice, monkeys as well as humans etc. Using these molecular scissors, one can engineer the genetic material in a variety of ways – one can make specific mutations by changing the sequence of bases or make insertions and deletions at the desired gene locus. Although a number of other tools are available to do this job, CRISPR has been proved superior to those due to its simple and efficient methodology.

Using these molecular scissors, one can engineer the genetic material in a variety of ways – one can make specific mutations, insertions, and deletions at the desired gene locus to alter gene function. Although a number of other tools are available to do this job, CRISPR has been proved superior to those due to its simple and efficient methodology.

Use of CRISPR in detecting diseases

Some pathogens, such as viruses and bacteria, during infection, integrate some of their genetic material into the host genome. One set of the diagnostic techniques works on identifying this pathogenic material to detect their presence in our system. However, these methods have trade-offs among sensitivity, specificity, simplicity, cost, and speed. There is a need for newer techniques that can easily detect pathogens by identifying their nucleic acid content even when they are present at very low levels.

The new study by Feng Zhang, one of the pioneers of CRISPR, and his colleagues published in Science Journals, demonstrates how the CRISPR system could be turned into a simple yet extremely sensitive diagnostic tool for detecting nucleic acids from these pathogens into the host system.

This new method can identify the presence of viruses such as Zika and Dengue, pathogenic bacteria and could also be potentially used to screen other mutations, which might be implicated in physiological conditions such as cancer. In principle, this can be used in the detection of pathogens in various patients’ samples be it blood or urine or saliva.

“Nature is really amazing. Over the course of billions of years, it’s come up with all these very powerful enzyme systems, and by studying the basic biology of these systems, some of them will give rise to important applications – like genome editing, like diagnostics,” Zhang, of the Broad Institute of MIT and Harvard, told , The Washington Post

Advantages of CRISPR-based diagnostics

In addition to the ease of use, CRISPR is extremely sensitive detecting the Zika Virus with an Attomolar detection range. It is estimated that the test could cost as low as 61 cents. Thus, the ability to rapidly detect nucleic acids with high sensitivity and single-base specificity on a portable platform definitely gives CRISPR an edge over other diagnostic procedures.

“We showed that this system is very stable, so you can really put it on a piece of paper and it will survive. You don’t have to refrigerate it all the time,” Zhang said.

Co-author Jim Collins, also of the Broad Institute, said, “In this diagnostic application we are really harnessing the power and diversity of biology. I view it as a potentially transformative diagnostic platform.”

This Cas18 based detection system is termed as SHERLOCK, Specific High-Sensitivity Enzymatic Reporter UnLOCKing. Collins has reported that scientists behind SHERLOCK have filed for patents for this technique and might soon make this new tool available for laboratory screenings.